Radiology Review Manual (Dahnert, Radiology Review Manual)

Authors: Dahnert, Wolfgang

Title: Radiology Review Manual, 6th Edition

Copyright 2007 Lippincott Williams & Wilkins

> Table of Contents > Obstetrics and Gynecology

Obstetrics and Gynecology

Differential Diagnosis of Obstetric and Gynecologic Disorders

2 obstetrics

Parity Nomenclature (for pregnancies <20 weeks)

Level I Obstetric Ultrasound

• Limited scope of examination to identify frequent causes of MS-AFP elevation in 20 50% of pregnancies:

  • Gestational age 2 weeks more advanced than estimated clinically (18%)

  • Multiple gestations (10%)

  • Unsuspected fetal demise (5%)

  • Obvious fetal NTD / abdominal wall defect

  Outcome:

  no cause identified in 50 80%

• Recommendation if level I ultrasound is unrevealing:

  • amniocentesis for AF-AFP (with normal results in >90%)

  • level II obstetric ultrasound (skipping amniocentesis)

Level II Obstetric Ultrasound

• Examination targeted for:

  • Open neural tube defect:

    • anencephaly, encephalocele, open spina bifida, amniotic band syndrome resulting in open neural tube defect

  • Closed neural axis anomaly:

    • hydrocephalus, Dandy-Walker malformation

  • Abdominal wall defect:

    • gastroschisis, omphalocele, gastropleuroschisis from amniotic band syndrome

  • Upper GI obstruction:

    • esophageal atresia tracheoesophageal fistula, duodenal obstruction

  • Cystic hygroma

  • Teratoma:

    • sacrococcygeal, lingual, retropharyngeal

  • Renal anomalies:

    Alpha-fetoprotein Levels
    Sample Site	Approximate Level (ng/mL)	Peak
    Maternal serum	30	30th 32nd week
    Amniotic fluid	20,000	2nd trimester
    Fetal plasma	3,000,000	14th 15th week

    • obstructive uropathy, renal agenesis, multicystic dysplastic kidney, congenital Finnish nephrosis

• Risk of fetal chromosomal anomaly is only 0.6 1.1% with normal level II sonogram!

Maternal serum screening

Alpha-fetoprotein

• = glycoprotein as major circulatory protein of early fetus

• Detectable in

  • fetal serum

    • concentration peaks at 14 15 weeks followed by progressive decline

  • amniotic fluid (AF-AFP) is a result of

    • fetal urination

    • fetal gastrointestinal secretions

    • transudation across fetal membranes (amnion, placenta)

    • transudation across immature fetal epithelium

    • concentration peaks early in 2nd trimester followed by progressive decline

  • maternal circulation (MS-AFP) secondary to leakage from amniotic fluid across the placenta

    • levels start to rise at 7th week, peak at 32nd week, and decline toward end of pregnancy

    • Either high / low MS-AFP is associated with 34% of all major congenital defect

• At the end of the 1st trimester AFP is present:

  in fetal plasma	in milligram	quantities
  in amniotic fluid	in microgram	quantities
  in maternal serum	in nanogram	quantities

  Reported in MoM =

  multiples of mean to standardize interpretation among laboratories

Elevated Alpha-fetoprotein

• screening at 16 18 weeks GA

• Values must be corrected for dates, maternal weight, race, presence of diabetes (diabetes has depressing effect on MS-AFP so that lower levels may be associated with NTDs)

• Associated with:

  • LABORATORY ERROR

  • ERRONEOUS DATES (18%):

    • GA 2 weeks more advanced sonographically than by clinical estimate (AFP levels rise 15% per week during 16 18-week window)

  • MULTIPLE GESTATIONS (14%)

  • FETAL DEMISE (7%) / fetal distress / threatened abortion

  • FETAL ANOMALIES (61%)

    • Neural tube defects (51%):

      • [anencephaly (30%), myelomeningocele (18%), encephalocele (3%), forebrain malformation]

        P.996

        Prevalence:

        1.6:1,000 births in USA; 6:1,000 births in Great Britain

      • In 90% as 1st time event!

        Risk of recurrence:

        3% after one affected child; 6% after 2 affected children

    • Ventral wall defects (21%)

      • (gastroschisis, omphalocele): sensitivity of 50%

    • Proximal fetal gut obstruction

      • (esophageal / duodenal atresia)

      • = diminished AFP degradation in small bowel

    • Cystic hygroma, teratoma (pharyngeal, sacral)

    • Amniotic band syndrome

      • (asymmetric cephalocele, gastropleuroschisis)

    • Renal abnormalities:

      • multicystic dysplastic kidney, renal agenesis, pelviectasis, congenital Finnish nephrosis (typically 10 MoM + negative amniotic fluid acetylcholinesterase)

    • Oligohydramnios

  • PLACENTAL LESION

    • altering the placentomaternal barrier

      • Chorioangioma

      • Peri- and intraplacental hematoma

        • resulting in fetomaternal hemorrhage

      • Placental lakes, infarct, intervillous thrombosis

  • LOW BIRTH WEIGHT

  • Normal pregnancy + MATERNAL DISORDER

    • Hepatitis

    • Hepatoma

  • Fetal-maternal blood mixing:

    • collection of MS-AFP samples after amniocentesis

      mnemonic:

      GEM MINER CO

    • Gastroschisis

    • Esophageal atresia

    • Multiple gestations

    • Mole

    • Incorrect menstrual dates

    • Neural tube defects

    • Error (laboratory)

    • Renal disease in fetus (autosomal recessive polycystic kidney disease, renal dysplasia, obstructive uropathy, congenital Finnish nephrosis)

    • Chorioangioma

    • Omphalocele

Elevated Maternal Serum AFP (MS-AFP)

• = defined as 2.5 MoM / equivalent to the 5th percentile; 4.5 MoM for multiple gestations

• Power of detection at 2.5 MoM cutoff:

  • 98% of gastroschisis

  • 90% of anencephalic fetuses

  • 75 80% of open spinal defects

  • 70% of omphaloceles

  Incidence:

  2 5% screen-positive rate (in 16% normal MS-AFP on retesting); 6 15% of fetuses have some type of major congenital defect; in 1.3:1,000 tests fetal anomaly detected

• The higher the AFP elevation the higher the probability of fetal anomalies

• 20 38% of women with unexplained high MS-AFP (ie, in absence of fetal abnormality) suffer adverse pregnancy outcomes (premature birth, preeclampsia, 2 4 IUGR, 10 perinatal mortality, 10 placental abruption)!

Elevated Amniotic Fluid AFP (AF-AFP)

• = defined as 2 MoM (<2 MoM has a 97% NPV)

  Incidence:

  <10% of women with elevated MS-AFP and unrevealing level I US exam

• amniotic fluid also tested for karyotype + acetylcholinesterase (= neurotransmitter enzyme present when neural tissue is exposed)

• 66% of fetuses of women with elevated AF-AFP levels are normal!

• A targeted level II ultrasound exam will show fetal anomalies in 33%!

Low Alpha-fetoprotein

• = MS-AFP 0.5 / AF-AFP 0.72 MoM

• Autosomal trisomy syndromes (trisomy 21, 18, 13)

  • 20% of trisomy 21 fetuses are found in women with low MS-AFP after adjustment for age!

• Absence of fetal tissues (eg, hydatidiform mole)

• Fetal demise

• Misdated pregnancy

• Normal pregnancy

• Patient not pregnant

Use of Karyotyping

• FETAL ANOMALIES

  • CNS anomalies: holoprosencephaly (43 59%), Dandy-Walker malformation (29 50%), cerebellar hypoplasia, agenesis of corpus callosum, myelomeningocele (33 50%)

  • Cystic hygroma (72%): Turner syndrome

  • Omphalocele (30 40%)

  • Cardiac malformations

  • Nonimmune hydrops

  • Duodenal atresia

  • Severe early-onset IUGR: trisomy 18, 13, triploidy

  • Diaphragmatic hernia

  • Bone-echodense bowel (20%): trisomy 21

• MATERNAL RISK FACTORS

  • Advanced age

  • Low serum alpha-fetoprotein

  • Abnormal triple screen of maternal serum

  • History of previous chromosomally abnormal pregnancy (1% risk of recurrence)

• PLANNED INTENSE INTRAUTERINE MANAGEMENT

• Fetal anomalies not associated with chromosomal anomalies:

  • Gastroschisis

  • Unilateral renal anomaly

  • Intestinal obstruction distal to duodenal bulb

  • Off-midline unilateral cleft lip

  P.997

  • Fetal teratoma (sacrococcygeal / anterior cervical)

  • Isolated single umbilical artery

Amniotic fluid volume

• Production:

  • 1st trimester: dialysate of maternal + fetal serum across the noncornified fetal skin

  • 2nd + 3rd trimester: fetal urine (600 800 cm³/day near term), fetal lungs (600 800 cm³/day near term), amniotic membrane

• Absorption:

  • fetal swallowing + GI absorption, fetal lung absorption, clearance by placenta

• Assessment of amniotic fluid volume by:

  • Subjective assessment ( Gestalt method):

    • quick + efficient, accounts for GA-related variations in fluid volume, considered the most accurate if performed by experienced operator, operator + interpreter must be identical, no documentation, variations on serial scans difficult to appreciate

  • Depth of largest vertical pocket:

    • simple + quick (used in BPP), pockets >2 cm may be found in crevices between fetal parts with moderately severe oligohydramnios, does not account for GA-related variations

  • Four-quadrant Amniotic Fluid Index (AFI):

    • fairly quick, probably correlates better with fluid volume than any single measurement, may not accurately reflect overall fluid volume, may be affected by fetal movement during measurements

      Aneuploid Risk of Major Anomalies

      Structural Defect	Incidence	Aneuploidy
      		Risk	Most common
      Cystic hygroma	1:6,000	60-75%	45X,21,18,13, XXY
      Hydrops	1:4,000	30 80%	13,21,18,45X
      Holoprosencephaly	1:16,000	40 60%	13,18,18p
      Cardiac defects	1:125	5 30%	21,18,13,22
      AV canal	40 70%	21
      Omphalocele	1:5,800	30 40%	13,18
      Duodenal atresia	1:10,000	20 30%	21
      Diaphragmatic hernia	1:4,000	20 25%	13,18,21,45X
      Bladder outlet obstruction	1:1,000	20 25%	13,18
      Limb reduction	1:2,000	8%	18
      Clubfoot	1:830	6%	18,13,4p-,18q-
      Hydrocephalus	1:1,250	3 8%	13,18, triploidy
      Facial cleft	1:700	1%	13,18, deletions
      Prune belly	1:40,000	low	18,13,45X
      Single umbilical artery	1:100	minimal
      Bowel obstruction	1:4,000	minimal
      Gastroschisis	1:12,000	minimal

  • Planimetric measurement of total intrauterine volume

  • Dye / para-amino hippurate dilution technique:

    • 800 cm³ at 34 weeks, 500 cm³ >34 weeks

Polyhydramnios

• = amniotic fluid volume >1,500 2,000 cm³ at term

  Incidence:

  1.1 2 3.5%

• fetus does not fill the AP diameter of uterus

• single largest pocket devoid of fetal parts / cord >8 cm in vertical direction

• AFI 20 24 cm

  Prognosis:

  64% perinatal mortality with severe polyhydramnios

• Etiology:

  • IDIOPATHIC (35%)

    Associated with:	macrosomia in 19 37%
    Suggested cause:

    • increased renal vascular flow

    • bulk flow of water across surface of fetus + umbilical cord + placenta + membranes

  • MATERNAL CAUSES (36%)

    • Diabetes (25%)

    • Isoimmunization [Rh incompatibility (11%)]

    • Placental tumors: chorioangioma

  • FETAL ANOMALIES (20%)

    • gastrointestinal anomalies (6 16%):

      • impairment of fetal swallowing (esophageal atresia in 3%); high intestinal atresias / obstruction of duodenum / proximal small bowel (1.2 1.8%), omphalocele, meconium peritonitis

    • nonimmune hydrops (16%)

    • neural tube defects (9 16%):

      • anencephaly, hydranencephaly, holoprosencephaly, myelomeningocele, ventriculomegaly, agenesis of corpus callosum, encephalocele, microcephaly

    • chest anomalies (12%):

      • diaphragmatic hernia, cystic adenomatoid malformation, tracheal atresia, mediastinal teratoma, primary pulmonary hypoplasia, extralobar sequestration, congenital chylothorax

    • skeletal dysplasias (11%):

      • dwarfism (thanatophoric dysplasia, achondroplasia), kyphoscoliosis, platyspondyly

    • chromosomal abnormalities (9%):

      • trisomy 21, 18, 13

    • cardiac anomalies (5%):

      • VSD, truncus arteriosus, ectopia cordis, septal rhabdomyoma, arrhythmia

    • genitourinary malformations:

      • unilateral UPJ obstruction, unilateral multicystic dysplastic kidney, mesoblastic nephroma

      Cause:

      ? hormonally mediated polyuria

    • miscellaneous (8%):

      • cystic hygroma, facial tumors, cleft lip / palate, teratoma, amniotic band syndrome, congenital pancreatic cyst

    • In polyhydramnios efforts to detect fetal anomalies should be directed at SGA fetuses!

      mnemonic:

      TARDI

• Twins

P.998

• Anomalies, fetal

• Rh incompatibility

• Diabetes

• Idiopathic

Oligohydramnios

• = amniotic fluid volume <500 cm³ at term

• single largest pocket devoid of fetal parts / cord 1 2 cm in vertical direction

• AFI 5 7 cm

  Etiology:
  mnemonic:	DRIPP

  • Demise of fetus / Drugs (Motrin therapy for tocolysis of preterm labor)

  • Renal anomalies, bilateral (= inadequate urine production): renal agenesis / dysgenesis, infantile polycystic kidney disease, prune belly syndrome, posterior urethral valves, urethral atresia, cloacal anomalies

    • 20-fold increase in incidence of fetal anomalies with oligohydramnios!

      N.B.:

      bilateral renal obstruction, if combined with intestinal obstruction, may be associated with polyhydramnios

  • IUGR (reduced renal perfusion)

  • Premature rupture of membranes (most common)

  • Postmaturity

Abnormal first trimester findings

First Trimester Bleeding

• = VAGINAL BLEEDING IN FIRST TRIMESTER

• INTRAUTERINE conceptus IDENTIFIED

  • Threatened abortion

  • Embryonic demise

  • Blighted ovum

  • Gestational trophoblastic disease

  • Implantation bleed (3 4 weeks after last menstrual period)

  • Subchorionic hemorrhage

  • Low-lying placenta previa

  • Twin loss

• NORMAL ENDOMETRIAL CAVITY

  • with -hCG level >1,800 mlU/mL

    • Recent spontaneous abortion

    • Ectopic pregnancy

  • with -hCG level <1,800 mlU/mL

    • Very early IUP

    • Ectopic pregnancy

• SAC VULNERABILITY

  • Leiomyoma

  • Intrauterine contraceptive device

Abnormal Sonographic Findings in 1st Trimester

• Embryonic demise = abortion (clinical term)

• Nondevelopment = blighted ovum

• Maldevelopment = hydatidiform mole

Empty Gestational Sac

• Normal early IUP between 5 and 7 weeks MA

• Blighted ovum

Gestational Sac in Low Position

• Abortion in progress

  • no placental blood flow

• Cervical ectopic pregnancy

• Fundal fibroid compressing sac downward

Positive -hCG without IUP

• HCG-producing tumor (rare)

• Ectopic pregnancy

• Recent / incomplete abortion

• Early intrauterine pregnancy

Thickened Central Cavity Complex

• Intrauterine blood

• Retained products of conception following an incomplete spontaneous abortion

• Early intrauterine not yet visible pregnancy

• Decidual reaction secondary to ectopic pregnancy

Uterus Large for Dates

• Multiple gestation pregnancy

• Inaccurate menstrual history

• Fibroids

• Polyhydramnios

• Hydatidiform mole

• Fetal macrosomia

Intrauterine membrane in pregnancy

• MEMBRANE OF MATERNAL ORIGIN

  • Uterine septum

    • = incomplete resorption of sagittal septum between the fused two m llerian ducts

  • Amniotic sheet / shelf

    • = folding of amniochorionic membrane around uterine synechia

    • synechia often thins during uterine stretching + disappears as pregnancy progresses

• MEMBRANE OF FETAL ORIGIN

  • Intertwin membrane

    • = apposing membrane of multiple pregnancy

  • Amniotic band

    • = rent within amnion

  • Chorioamnionic separation

    • = incomplete fusion / hemorrhagic separation of amnion (= inner membrane) and chorion (= outer membrane)

  • Subchorionic hemorrhage = chorioamnionic elevation

    • = separation of chorionic membrane from decidua

    • implantation bleed of early pregnancy

P.999

• FIBRIN STRAND

  Cause:	hemorrhage during transplacental amniocentesis
  mnemonic:	STABS

  • Separation (chorioamnionic)

  • Twins (intertwin membrane)

  • Abruption

  • Bands (amniotic band syndrome)

  • Synechia

Dilated Cervix

• Inevitable abortion

• Premature labor

  • = spontaneous onset of palpable, regularly occurring uterine contractions between 20 and 37 weeks MA

• Incompetent cervix

Placenta

Abnormal Placental Size

• Placental mass tends to reflect fetal mass!

• ENLARGEMENT OF PLACENTA = Placentomegaly

  • = >5 cm thick in sections obtained at right angles to long axis of placenta

    • maternal disease

      • Maternal diabetes (= villous edema)

      • Chronic intrauterine infections (eg, syphilis)

      • Maternal anemia (= normal histology)

      • Alpha-thalassemia

    • fetal disease

      • Hemolytic disease of the newborn (= villous edema + hyperplasia) due to immunologic incompatibility including Rh sensitization

      • Umbilical vein obstruction

      • Fetal high-output failure:

        • large chorioangioma, arteriovenous fistula

      • Fetal malformation:

        • Beckwith-Wiedemann syndrome, sacrococcygeal teratoma, chromosomal abnormality, fetal hydrops

      • Twin-twin transfusion syndrome

    • fetomaternal hemorrhage

    • placental abnormalities

      • Molar pregnancy

      • Chorioangioma

      • Intraplacental hemorrhage

        mnemonic:

        HAD IT

        • Hydrops

        • Abruption

        • Diabetes mellitus

        • Infection

        • Triploidy

• DECREASE IN PLACENTAL SIZE

  • Preeclampsia

    • associated with placental infarcts in 33 60%

  • IUGR

  • Chromosomal abnormality

  • Intrauterine infection

Vascular Spaces of the Placenta

• Placental cysts

  • = large fetal veins located between amnion + chorion anastomosing with umbilical vein

  • sluggish blood flow (detectable by real-time observation)

• Basal veins

  • = decidual + uterine veins

  • lacy appearing network of veins underneath placenta

    DDx:	placental abruption

• Intraplacental venous lakes

  • intraplacental sonolucent spaces

  • whirlpool motion pattern of flowing blood

Macroscopic Lesions of the Placenta

• Intervillous thrombosis (36%)

  • = intraplacental areas of hemorrhage

    Etiology:

    breaks in villous capillaries with bleeding from fetal vessels

  • irregular sonolucent intraplacental lesions (mm to cm range)

  • blood flow may be observed within lesion

    Significance:

    fetal-maternal hemorrhage (Rh sensitization, elevated AFP levels)

• Perivillous fibrin deposition (22%)

  • = nonlaminated collection of fibrin deposition

    Etiology:	thrombosis of intervillous space
    Significance:	none

• Septal cyst (19%)

  Etiology:

  obstruction of septal venous drainage by edematous villi

  • 5 10-mm cyst within septum

  Significance:

  none

• Placental infarct (25%)

  • = coagulation necrosis of villi

    Etiology:

    disorder of maternal vessels, retroplacental hemorrhage

  • not visualized unless hemorrhagic

  • well-circumscribed mass with hyperechoic / mixed echo pattern

    Significance:

    dependent on extent + associated maternal condition

• Subchorionic fibrin deposition (20%)

  • = laminated collection of fibrin deposition

    Etiology:

    thrombosis of maternal blood in subchorionic space

  • subchorionic sonolucent area

    Significance:

    none

• Massive subchorial thrombus

  • = Breus MOLE = preplacental HEMORRHAGE

Placental Tumor

• TROPHOBLASTIC

  • Complete hydatidiform mole

  • Partial hydatidiform mole

  • Invasive mole

  • Choriocarcinoma

• Nontrophoblastic

  • Chorioangioma (in up to 1% of placentas)

  • Teratoma (rare)

  P.1000

  • Metastatic lesion (rare): melanoma, breast carcinoma, bronchial carcinoma

Unbalanced Intertwin Transfusion

• = unbalanced intertwin transfusion through vascular anastomoses between the two circulations of monochorionic twins

• ACUTE = Twin-embolization syndrome

• CHRONIC = Twin-twin transfusion syndrome

• REVERSE = Acardiac twinning

Umbilical cord

Abnormal Cord Attachment

• Marginal cord attachment (7%)

  • = battledore placenta (flat wooden paddle used in an early form of badminton)

  • no clinical significance

• Velamentous insertion of cord (1%)

• Vasa previa

Umbilical Cord Lesions

• Umbilical cord cysts persisting into 2nd + 3rd trimester are frequently accompanied by fetal anomalies (hernia, intestinal obstruction, urinary tract obstruction, urachal anomalies, omphalocele, cardiac defect, trisomy 18)!

• DEVELOPMENTAL CORD LESION

  • Umbilical hernia

    • = protrusion from anterior abdominal wall with normal insertion of umbilical vessels

    • Predisposed:

      • Blacks, low-birth-weight infants, trisomy 21, congenital hypothyroidism, Beckwith-Wiedemann syndrome, mucopolysaccharidoses

        Prognosis:

        spontaneous closure in first 3 years of life

  • Omphalomesenteric duct cyst

    • near fetal end of cord + eccentric in cord

  • Allantoic cyst

    • = remnant of umbilical vesicle / allantois; usually degenerates by 6 weeks

      Histo:

      lined by single layer of flattened epithelium

    • near fetal end of cord + in center of cord

  • Amniotic inclusion cyst

    • = amniotic epithelium trapped within umbilical cord

  • Mucoid degeneration of umbilical cord

    • = umbilical cord pseudocyst

    • = liquefaction of Wharton jelly / edema

    • focal thickening of Wharton jelly, usually near umbilicus

    • usually resolved by 12 weeks MA

    • Associated commonly with omphalocele

  • Noncoiled straight cord

    • counterclockwise:clockwise umbilical cords = 7:1

    • right-handed:left-handed persons = 7:1

      Incidence:

      3.7 5%

    • absent vascular coiling for entire length of visible cord

      At risk for:

      intrauterine death (8%), stillbirth, fetal anomalies (24%), prematurity, intrapartum heart rate decelerations, fetal distress, meconium staining

• ACQUIRED CORD LESION

  • False knot

    • exaggerated looping of cord vessels causing focal dilatation of cord

    • focal accumulation of Wharton jelly

    • varix of umbilical vessel

    • knoblike protrusion / bulge of cord

  • True knot

    Incidence:	1% of pregnancies
    Cause:	excessive fetal movements
    Predisposed:	long cord, polyhydramnios, small fetus, monoamniotic twins

    • local distension / thrombosis of umbilical vein near cord knot resembling an umbilical cyst

    • tortuosity of cord at level of knot

      Cx:	vascular occlusion + fetal death in utero
      OB management:	expectant

  • Umbilical cord hematoma

    • = rupture of the wall of the umbilical vein secondary to mechanical trauma (torsion, loops, knots, traction) / congenital weakness of vessel wall

      Incidence:	1:5,505 to 1:12,699 deliveries
      Location:	near fetal insertion of umbilical cord (most common)

    • hyper- / hypoechoic mass 1 2 cm in size, multiple (in 18%)

      Cx:	rupture into amniotic cavity with exsanguination
      Prognosis:	52% overall perinatal fetal mortality

  • Neoplasm

    • Angiomyxoma / hemangioma of cord

      Incidence:	22 cases in literature
      Histo:	multiple vascular channels lined by benign endothelium surrounded by edema + myxomatous degeneration of Wharton jelly
      Associated with:	elevated -fetoprotein level
      Location:	more frequently near placental end of umbilical cord

      • hyperechoic / multicystic mass within cord

      • may be associated with pseudocyst

        • (= localized collection of edema)

          Cx:	premature delivery, stillbirth, hydramnios, nonimmune hydrops, massive hemorrhage due to rupture

    • Other tumors: myxosarcoma, dermoid, teratoma

  • Umbilical vein varix

    Incidence:	<4% of all umbilical cord abnormalities
    Site:	intraamniotic, intraabdominal

    • fusiform dilatation of umbilical vein

    Cx:	(1) Thrombosis with subsequent fetal death
    	(2) Partial thrombosis with IUGR
    Prognosis:	usually no clinical significance

  • Umbilical artery aneurysm

P.1001

Small-for-gestational age fetus (SGA)

• = generic clinical term describing a group of perinates at / below the 10th percentile for gestational age without reference to etiology

• Fetus of appropriate growth (misdiagnosed as small)

• Small normal fetus = constitutionally small fetus (80 85%)

  • No indication for surveillance / intervention!

• Small abnormal fetus = primary growth failure associated with karyotype anomaly / fetal infection (5 10%)

  • Active intervention is of no benefit!

• Dysmature fetus = IUGR = growth failure as a result of uteroplacental insufficiency (10 15%)

  • Intensive management is likely of benefit!

Fetal Overgrowth Disorder

• Beckwith-Wiedemann syndrome

• Simpson-Golabi-Behmenl syndrome

• Perlmann syndrome

Fetal skeletal dysplasia

• = DWARFISM

• = heterogeneous group of bone growth disorders resulting in abnormal shape + size of the skeleton

• More than 200 skeletal dysplasias are known, but only a few are frequent:

  • thanatophoric dysplasia

  • osteogenesis imperfecta type II

  • achondrogenesis

  • heterozygous achondroplasia

• Birth prevalence:

  • 3:10,000 7.6:10,000 births for all skeletal dysplasias;

  • 5:10,000 births for lethal skeletal dysplasias

    Comparison of Antenatal Sonographic Findings in Fetal Overgrowth Syndromes

    Finding	Perlman	BWS	SGBS
    Macrosomia	X	X	X
    Polyhydramnios	X	X	X
    Hepatomegaly	X	X	X
    Nephromegaly	X	X	X
    Hydronephrosis	X	X	X
    Cystic hygroma	X
    Choroid plexus cyst	X
    Agenesis of corpus callosum	X
    Ascites	X
    Macrocephaly	X		X
    Cardiomegaly	X	X
    Cardiac defects		X	X
    Macroglossia		X	X
    Cleft lip / palate		X	X
    Hydrops		X	X
    Placentomegaly		X
    Omphalocele / umbilical hernia		X
    Polydactyly / syndactyly			X
    BWS = Beckwith-Wiedemann syndrome; SGBS =Simpson-Golabi-Behmenl syndrome

    Prevalence of fetal skeletal Dysplasias

    	Birth Prevalence	Perinatal Deaths
    Thanatophoric dysplasia	0.69:10,000*	1:246
    Achondroplasia	0.37:10,000*	none
    Achondrogenesis, type I	0.23:10,000*	1:639
    Achondrogenesis, type II	0.25:10,000*
    Osteogenesis imperf. type II	0.18:10,000*	1:799
    Osteogenesis imperf., others	0.18:10,000*	none
    Asphyxiating thoracic dysplasia	0.14:10,000*
    Hypophosphatasia	0.10:10,000*
    Chondrodysplasia punctata, rhizo	0.09:10,000*	none
    Camptomelic dysplasia	0.05:10,000*	1:3,196
    Chondroectodermal dysplasia	0.05:10,000*	1:3,196
    Cleidocranial dysplasia	0.05:10,000*
    Diastrophic dysplasia	0.02:10,000*
    	* = lethal dysplasias

    Prognosis:	51% lethal due to hypoplastic lungs:
    	23% stillbirths, 32% death in 1st week of life

• Associated with:

  • polyhydramnios

  • small thorax

  • morphologically abnormal bones

• shortening of long bones (common characteristic)

  • Femur length >5 mm below 2 standard deviations suggests skeletal dysplasia!

• femur length / foot length ratio <0.9

• moderate limb shortening of 40 60% of the mean in thanatophoric dysplasia + OI type II

• severe limb shortening of >30% of the mean in achondrogenesis

  DDx features:	mineralization, bowing, fractures, number of digits, fetal movement, thoracic measurement, associated anomalies, age of onset
  DDx:	constitutionally short limbs, severe IUGR

• see also DWARFISM

Fetal Hand Malformation

Polydactyly

• trisomy 13, short-rib-polydactyly syndrome, asphyxiating thoracic dystrophy (Jeune syndrome), Smith-Lemli-Opitz syndrome

  • Postaxial polydactyly

    • chondroectodermal dysplasia (Ellis-van Creveld syndrome), Meckel-Gruber syndrome, hydrolethalus syndrome

  • Preaxial polydactyly

    • orofaciodigital syndrome

Syndactyly

• Apert syndrome, triploidy, Roberts syndrome

Clinodactyly

• trisomy 21, triploidy

Overlapping Digit

• trisomy 18

P.1002

Hitchhiker's Thumb

• diastrophic dysplasia

Flexion Contractures

• trisomy 13 + 18, fetal akinesia deformation sequence

Limb Reduction

• congenital varicella, hypoglossia-hyperdactyly syndrome

Amputation

• amniotic band syndrome

Fetal CNS anomalies

• ventricular atrium + cisterna magna are two sensitive anatomic markers for normal brain development!

• HYDROCEPHALUS

  • Aqueductal stenosis

  • Communicating hydrocephalus

  • Dandy-Walker malformation

  • Choroid plexus papilloma

• NEURAL TUBE DEFECT

  Incidence:	1:500 600 live births
  Risk of recurrence:	3 4%

  • Spina bifida

  • Anencephaly

  • Acrania

  • Encephalocele (8 15%)

  • Porencephaly

  • Hydranencephaly

  • Holoprosencephaly

  • Iniencephaly

  • Microcephaly

  • Agenesis of corpus callosum

  • Lissencephaly

  • Arachnoid cyst

  • Choroid plexus cyst

  • Vein of Galen aneurysm

  Associated with:	trisomy 13 and 18
  Increased risk:	low parity, low socioeconomic status, relative infertility, diabetes, obesity, anticonvulsants, folate deficiency

• INTRACRANIAL NEOPLASM

  • Teratoma (>50%): benign / malignant

    Location:

    originate from base of skull

  • Glioblastoma

  • Astrocytoma

Fetal Ventriculomegaly

• Cause:

  • Morphologic anomaly (70 80%):

    • Spina bifida (30 65%)

    • Dandy-Walker malformation

    • Encephalocele

    • Holoprosencephaly

    • Agenesis of corpus callosum

  • Abnormal karyotype (10 20%)

  • Viral infection

  • 20 40% of concurrent anomalies are missed by ultrasound!

• dangling choroid plexus

• width of ventricular atrium >10 mm

Isolated Mild Ventriculomegaly

• = atrial width of 10 15 mm

  Prevalence:	1:700 in low-risk population
  	Most common brain anomaly on prenatal sonograms

• Associated structural anomalies (9%):

  • periventricular leukomalacia, subependymal / germinal matrix hemorrhage, partial agenesis of corpus callosum, heterotopia, parenchymal dysplasia

    Associated chromosomal anomalies:	in 4%
    Recommendation:	MRI to diagnose associated structural anomalies
    Prognosis:	80% with isolated mild ventriculomegaly have normal motor + intellectual function at 12 months of age

Lemon Sign

• = flat / inwardly scalloped contour of both frontal bones

• Spina bifida

  Prevalence for fetuses 24 weeks:

  98%

  • (90 93% sensitive, 98 99% specific, 84% PPV for high-risk population, 6% PPV for low-risk population)

    Prevalence for fetuses >24 weeks:

    13%

  • (disappears in 3rd trimester)

• Encephalocele

• Agenesis of corpus callosum

• Thanatophoric dysplasia

• Cystic hygroma

• Diaphragmatic hernia

• Fetal hydronephrosis

• Umbilical vein varix

• Normal fetus (in 0.7 1.3%)

Prenatal Intracranial Calcifications

• Toxoplasmosis

• CMV infection

• Tuberous sclerosis

• Sturge-Weber syndrome

• Venous sinus thrombosis

• Teratoma

Cystic Intracranial Lesion

• Choroid plexus cyst

• Hydrocephalus, Holoprosencephaly, Hydranencephaly

• Agenesis of corpus callosum + cystic dilatation of 3rd ventricle

• Porencephaly

• Vein of Galen aneurysm

• Arachnoid cyst

• Neoplasm (cystic teratoma)

Abnormal Cisterna Magna

• Normal size between 15 and 25 weeks MA:

  • >2 to <10 mm (usually 4 9 mm) in 94 97% of fetuses

• SMALL CISTERNA MAGNA + banana sign

  • Chiari II malformation (with myelomeningocele)

  • Occipital cephalocele

  P.1003

  • Severe hydrocephalus

• LARGE CISTERNA MAGNA

  • Megacisterna magna

    • cerebellum + vermis remain intact

  • Arachnoid cyst

    • en bloc displacement of cerebellum + vermis

  • Cerebellar hypoplasia

  • Dandy-Walker syndrome (with vermian agenesis)

Fetal orbital anomalies

Hypotelorism

• Holoprosencephaly

• Chromosomal abnormalities: trisomy 13

• Microcephaly, trigonocephaly

• Maternal phenylketonuria

• Meckel-Gruber syndrome

• Myotonic dystrophy

• Williams syndrome

• Oculodental dysplasia

Hypertelorism

• Median cleft syndrome: cleft lip / palate

• Craniosynostosis: Apert /Crouzon syndrome

• Pena-Shokeir syndrome

• Frontal / ethmoidal, sphenoidal encephalocele

• Dilantin / phenytoin effect

Orbital and Periorbital Masses

• Dacryocystocele

• Anterior encephalocele

• Glioma

• Hemangioma

• Teratoma

Fetal neck anomalies

• Cervical myelomeningocele

• Occipital cephalocele

• Cystic hygroma / lymphangioma

• Teratoma

• Branchial cleft cyst

• Enlarged thyroid

• Sarcoma

Nuchal Skin Thickening

• = NUCHAL SONOLUCENCY / FULLNESS / EDEMA

• = skin thickening of posterior neck measured between calvarium + dorsal skin margin

  • 3 mm during 9 13 weeks MA

  • 5 mm during 14 21 weeks MA

  • 6 mm during 19 24 weeks MA

  • The smallest measurement should be used!

  Image plane:	axial / transverse image (slightly craniad to that of the BPD measurement) that includes cavum septi pellucidi, cerebellar hemisphere and cisterna magna (transcerebellar diameter view)
  Incidence:	among the most common anomaly in 1st trimester + early 2nd trimester

• Cause:

  • NORMAL VARIANT (0.06%)

  • CHROMOSOMAL DISORDERS

    • trisomy 21 (in 45 80%), Turner syndrome (45 X0), Noonan syndrome, trisomy 18, XXX syndrome, XYY syndrome, XXXX syndrome, XXXXY syndrome, 18p-syndrome, 13q-syndrome

    • 30 40% of fetuses with Down syndrome have nuchal skin thickening!

  • nonchromosomal DISORDERS

    • Multiple pterygium syndrome = Escobar syndrome

    • Klippel-Feil syndrome (fusion of cervical vertebrae, CHD, deafness (30%), cleft palate

    • Zellweger syndrome = cerebrohepatorenal syndrome (large forehead, flat facies, macrogyria, hepatomegaly, cystic kidney disease, contractures of extremities)

    • Robert syndrome

    • Cumming syndrome

• larger lymphangiomas with radiating septations are usually found with trisomy 18

• nuchal fullness 3 mm during 1st trimester is seen in trisomy 21 / 18 / 13 (30 50% PPV)

• often reverting to normal by 16 18 weeks

• septations within nuchal translucency carries a 20- to 200-fold risk for chromosomal anomalies compared with normal

  Sensitivity:	2 44 75% for detection of trisomy 21
  Specificity:	99% for detection of trisomy 21
  PPV:	69%
  Positive screen:	1.2 3% in general population (exceeding 0.5% risk of amniocentesis)
  False positives:	0.5 2 8.5%
  OB management:	thorough sonographic evaluation at 18 20 weeks MA
  DDx:	chorioamnionic separation

Protruding Tongue

• Macroglossia

• Lymphangioma of the tongue

Macroglossia

• Beckwith-Wiedemann syndrome

• Down syndrome

• Hypothyroidism

• Mental retardation

Fetal chest anomalies

Pulmonary Hypoplasia

• Cause:

  • Prolonged oligohydramnios (20 25%)

  • Skeletal dysplasia (small thorax)

  • Intrathoracic mass (lung compression)

  • Large hydrothorax (lung compression)

  • Neurologic condition (reduced breathing activity)

  • Chromosomal abnormality

  • CHD with R-sided cardiac obstructing lesion

P.1004

• thoracic circumference (TC) <5th percentile for EGA

• declining TC:AC ratio from >0.80 (75% sensitive, 80 90% specific); not applicable for intrathoracic masses

Intrathoracic Mass

• in order of frequency:

  • Diaphragmatic hernia / eventration

  • Cystic adenomatoid malformation

  • Bronchopulmonary sequestration

  • Bronchogenic cyst with bronchial compression

  • Bronchial atresia

Unilateral Chest Mass

• Congenital diaphragmatic hernia

• Cystic adenomatoid malformation

• Bronchopulmonary sequestration

• Bronchogenic cyst

• Unilateral bronchial atresia / stenosis

Bilateral Chest Masses

• Laryngeal / tracheal atresia

• Bilateral cystic adenomatoid malformation

• Bilateral congenital diaphragmatic herniae

Mediastinal Mass

• Goiter

• Cystic hygroma

• Pericardial teratoma

• Neuroblastoma

Cystic Chest Mass

• Bronchogenic cyst

• Enteric cyst

• Neurenteric cyst

• Cystic adenomatoid malformation (type I)

• Congenital diaphragmatic hernia

• Pericardial cyst

• Mediastinal meningocele

Complex Chest Mass

• Congenital diaphragmatic hernia

• Cystic adenomatoid malformation (type I, II, III)

• Pulmonary sequestration

• Complex enteric cyst

• Pericardial teratoma

Solid Chest Mass

• Congenital diaphragmatic hernia (bowel liver)

• Cystic adenomatoid malformation type III

• Pulmonary sequestration

• Obstructed lung from bronchial atresia, laryngeal atresia, bronchogenic cyst

• Bronchopulmonary foregut malformation

• Pericardial tumor

• Heterotopic brain tissue

Regressing Fetal Chest Mass

• Cystic adenomatoid malformation

• Bronchopulmonary sequestration

Chest Wall Mass

• Hemangioma

• Cystic hygroma

• Teratoma

• Hamartoma

• Thoracic myelomeningocele

Pleural Effusion

• Primary idiopathic chylothorax (most common)

• Hydrops fetalis (multiple causes)

• Chromosome anomaly: trisomy 21, 45 XO (mostly)

• Pulmonary lymphangiectasia / cystic hygroma

• Lung mass: cystic adenomatoid malformation, bronchopulmonary sequestration, congenital diaphragmatic hernia, chest wall hamartoma (uncommon)

• Pulmonary vein atresia

• Idiopathic

Fetal cardiac anomalies

• 90% occur as isolated multifactorial traits with a recurrence risk of 2 4%

• 10% are associated with multiple birth defects

• responsible for 50% of childhood deaths from congenital malformations

• Antenatal sonographic diagnosis to prompt cardiac evaluation:

  • ABNORMALITIES IN CARDIAC POSITION

  • CNS

    • Hydrocephalus

    • Microcephaly

    • Agenesis of corpus callosum

    • Encephalocele (Meckel-Gruber syndrome)

  • GASTROINTESTINAL

    • Esophageal atresia

    • Duodenal atresia

    • Situs abnormalities

    • Diaphragmatic hernia

  • VENTRAL WALL DEFECT

    • Omphalocele

    • Ectopia cordis

  • RENAL

    • Bilateral renal agenesis

    • Dysplastic kidneys

  • TWINS

    • Conjoined twins

Prenatal Risk Factors for Congenital Heart Disease

• FETAL RISK FACTORS

  • Symmetric IUGR

  • Arrhythmias

    • fixed fetal bradycardia (50%) 110 bpm

    • tachycardia (low risk)

    • irregular: PACs, PVCs (low risk)

  • Abnormal fetal karyotype

    • (CHD in Down syndrome in 40%; in trisomy 18 / 13 in >90%; in Turner syndrome in 35%)

  • Extracardiac somatic anomalies by US

    • omphaloceles (20%), duodenal atresia, hydrocephaly, spina bifida, VACTERL

  • Nonimmune hydrops (30 35%)

  • Oligo- / polyhydramnios

P.1005

• MATERNAL RISK FACTORS

  • Maternal heart disease (10%)

  • Insulin-dependent diabetes mellitus (4 5%)

  • Phenylketonuria (in 15% if maternal phenylalanine >15%)

  • Collagen vascular disease: SLE

  • Viral infection: rubella

  • Drugs

    • phenytoin (in 2% PS, AS, coarctation, PDA)

    • trimethadione (in 20% transposition, tetralogy, hypoplastic left heart)

    • sex hormones (in 3%)

    • lithium (7%): Ebstein anomaly, tricuspid atresia

    • alcohol (25% of fetal alcohol syndrome): VSD, ASD

    • retinoic acid = isotretinoin (?15%)

  • Paternal CHD (risk uncertain)

• MENDELIAN SYNDROMES

  • Tuberous sclerosis

  • Ellis-van Creveld syndrome

  • Noonan syndrome

• FAMILIAL RISK FACTORS FOR RECURRENCE OF HEART DISEASE

  overall incidence	: 6 8:1,000 live births
  affected sibling	: 1 4% (risk doubled)
  affected parent	: 2.5 4%

• In 50% of neonates with CHD there is no identifiable risk factor!

• Poor prognostic features:

  • Intrauterine cardiac failure (hydrops)

  • Severe trisomy (18, 13)

  • Hypoplastic left heart + endocardial fibroelastosis

  • Delivery in center without pediatric cardiology

In Utero Detection of Cardiac Anomalies

• ABNORMAL HEART POSITION

  • Diaphragmatic hernia

  • Lung anomaly

  • Pleural effusion

  • Cardiac defect

• CHAMBER ENLARGEMENT

  RA:	LA:
  1. Tricuspid regurgitation	1. Mitral stenosis
  2. Tricuspid valve dysplasia	2. Aortic stenosis
  3. Ebstein anomaly
  RV:	LV:
  1. Coarctation	1. Aortic stenosis
  2. Normal in 3rd trimester	2. Cardiomyopathy

• ABNORMAL FOUR-CHAMBER VIEW

  • Septal rhabdomyoma

  • Endocardial cushion defect

  • Ventricular septal defect

  • Ebstein anomaly

  • Single ventricle

• VENTRICULAR DISPROPORTION

  • Hypoplastic right / left ventricle

  • Hypoplastic aortic arch

  • Aortic / subaortic stenosis

  • Coarctation of aorta

  • Ostium primum defect

• INCREASED AORTIC ROOT DIMENSION

  • Tetralogy of Fallot

  • Truncus arteriosus

  • Hypoplastic left ventricle with transposition

• DECREASED AORTIC ROOT DIMENSION

  • Coarctation of aorta

  • Hypoplastic left ventricle

• 26 80% of serious cardiac anomalies can be detected on four-chamber view!

• Increased sensitivity >20 weeks + by including outflow views!

Structural Cardiac Abnormalities & Fetal Hydrops

• Atrioventricular septal defect + complete heart block

• Hypoplastic left heart

• Critical aortic stenosis

• Cardiac tumor

• Ectopia cordis

• Dilated cardiomyopathy

• Ebstein anomaly

• Pulmonary atresia

Fetal Echocardiographic Views

• FOUR-CHAMBER VIEW

  • Position of heart within thorax

  • Number of cardiac chambers

  • Ventricular proportion

  • Integrity of atrial + ventricular septa

  • Position + size + excursion of AV valves

• PARASTERNAL LONG-AXIS VIEW

  • = LEFT VENTRICULAR OUTFLOW TRACT VIEW

  • Continuity between ventricular septum + anterior aortic wall

  • Caliber of aortic outflow tract

  • Excursion of aortic valve leaflets

• SHORT-AXIS VIEW OF OUTFLOW TRACTS

  • Spatial relationship between aorta + pulmonary artery

  • Caliber of aortic + pulmonary outflow tracts

• AORTIC ARCH VIEW

• Identification of fetal RV:

  • RV lies closest to anterior chest wall

  • foramen ovale flap seen within LA

  • prominent moderator band + papillary muscles in RV

Echogenic Intracardiac Focus

• Isolated anomaly in 90%!

  Fetal Short-Axis View

  Fetal Four-Chamber View

  P.1006

  • Trisomy 21 (in 30% of affected fetuses)

  • Trisomy 13 (in 50% of affected fetuses)

  • Normal pregnancy (4% in a population at high risk for fetal anomalies)

Fetal gastrointestinal anomalies

• Esophageal atresia TE fistula

• Duodenal atresia

• Meconium peritonitis

• Hirschsprung disease

• Choledochal cyst

• Mesenteric cyst

Fetal Abdominal Wall Defect

• 1. Gastroschisis

• 2. Omphalocele spectrum:

  • upper abdominal wall defect

    • 3. Ectopia cordis

    • 4. Pentalogy of Cantrell

  • midabdominal wall defect: classic omphalocele

  • lower abdominal wall defect

    • 5. Bladder exstrophy

    • 6. Cloacal exstrophy

• 7.Amniotic band syndrome

• 8. Limb-body wall complex

Fetal Hepatomegaly

• CONGENITAL INFECTIONS

  • CMV

• SEVERE HEMOLYTIC DISEASE

• SYNDROMES

  • Beckwith-Wiedemann syndrome

  • Zellweger syndrome

Intraabdominal Echogenic Mass in Fetus

• Abdomen

  • Echogenic bowel

  • Enteric duplication cyst (rarely echogenic)

  • Subdiaphragmatic extralobar pulmonary sequestration (4:1 left-sided predominance)

• Liver

  • Hepatic hemangioma

  • Hepatic mesenchymal hamartoma composed of multiple microcysts

• Adrenal / renal

  • Neuroblastoma

  • Adrenal hemorrhage

  • Mesoblastic nephroma

Nonvisualization of Fetal Stomach

• Fetal swallowing begins at 11 weeks MA

• Cause:

  • Physiologic gastric emptying / intermittent swallowing

    • Repeat scan after 30 minutes!

  • Oligohydramnios

  • CNS depression / abnormalities impairing swallowing

  • Abnormal position of stomach:

    • stomach on contralateral side (situs inversus)

    • congenital diaphragmatic hernia

  • Esophageal atresia TE fistula

    • Nonvisualization of fetal stomach and polyhydramnios in 33% fetuses with esophageal atresia after 24 weeks MA!

  • Cleft lip / palate (impairing normal swallowing)

Double Bubble Sign

• = fluid-filled stomach + proximal duodenum

• A persistently fluid-filled duodenum is always abnormal!

• DUODENAL OBSTRUCTION

  • Duodenal atresia (usually not seen <24 weeks MA)

    Cause:

    in 30% due to Down syndrome

  • Severe duodenal stenosis

  • Duodenal web

  • Duodenal duplication cyst

• PERIDUODENAL ANOMALY

  • Ladd bands

  • Annular pancreas

  • Preduodenal portal vein

• DISTAL OBSTRUCTION

  • Midgut volvulus

  • Malrotation

• Ladd bands / malrotation

• Annular pancreas

• Duodenal atresia

• Stenosis (duodenal)

Dilated Bowel in Fetus

• Meconium ileus

  • All newborns with meconium ileus have cystic fibrosis!

  • 10 15% of newborns with cystic fibrosis present with meconium ileus!

• Apple peel atresia of small bowel

• Jejunal atresia

• Megacystis-microcolon-intestinal hypoperistalsis syndrome

• Colonic aganglionosis = Hirschsprung disease

  • (may be associated with Down syndrome)

• Anorectal atresia (associated with CNS abnormalities, part of VACTERL complex)

Bowel Obstruction in Fetus

• Pathologic types:

  • one / more transverse diaphragms

  • blind-ending loops connected by fibrous string

  • complete separation of blind-ending loops

  • apple-peel atresia of small bowel (occlusion of SMA branch)

    Associated with:

    GI anomalies in 45% (malrotation, duplication, microcolon, esophageal atresia)

P.1007

• multiple distended bowel loops >7 mm in diameter

• increased peristalsis

• polyhydramnios (if obstruction above level of mid jejunum; exceptions are esophageal atresia + TE fistula) due to fetal inability to cycle amniotic fluid through gut

Hyperechoic Fetal Bowel

• Most common echogenic mass in fetal abdomen

• Normal small bowel variant (especially <20 weeks MA) with resolution on follow-up sonogram toward end of 2nd trimester (in 50 70%)

• Normal colon variant in 3rd trimester 2 to echogenic meconium

• Meconium ileus

  • Increased abdominal echogenicity is seen in 60 70% of fetuses with cystic fibrosis!

• Chromosomal abnormality (3 25%)

  • Down syndrome (5 14%)

  • Trisomy 13, 18

  • Turner syndrome

• Severe IUGR (16%)

• Intraamniotic bleeding

  • with subsequent swallowing of blood by fetus

• Prognosis:

  • 5-fold increase in risk for adverse fetal outcome (due to chromosomal abnormality, other anomalies, placental abruption, perinatal death [8 16%], IUGR [67 23%])

  • 30 50% of fetuses with echogenic bowel in 2nd trimester will have poor outcome!

Intraabdominal Calcifications in Fetus

• Isolated liver calcifications are relatively frequent (1:1,750 pregnancies) and of no clinical significance!

Scattered Calcifications

• PERITONEAL

  • Meconium peritonitis

  • Plastic peritonitis associated with hydrometrocolpos

• CONGENITAL INFECTION

  • Toxoplasmosis

  • Cytomegalovirus

Focal Calcification

• TUMOR

  • Hepatoblastoma

  • Metastatic neuroblastoma

  • Hemangioma / hemangioendothelioma

  • Teratoma

  • Ovarian dermoid

• OTHERS

  • Fetal gallstones (>28 weeks EGA)

    Cause:	hemolytic disease, cholestasis, maternal drug use
    Prognosis:	resolution before / after delivery

Cystic Mass in Fetal Abdomen

• POSTERIOR MID ABDOMEN

  • Cysts of renal origin

  • Hydroureteronephrosis

  • Multicystic dysplastic kidney

  • Paranephric collection

• RIGHT UPPER QUADRANT

  • Liver cyst

  • Choledochal cyst

• LEFT UPPER QUADRANT

  • Splenic cyst

• ANTERIOR MID ABDOMEN

  • Gastrointestinal duplication cyst

  • Mesenteric cyst

  • Meconium pseudocyst

  • Dilated bowel

  • Urachal cyst

• LOWER ABDOMEN

  • Adnexal cyst: follicular cyst (most), corpus luteum cyst, theca lutein cyst, paraovarian cyst, teratoma, cystadenoma

    Cx of large cysts:	polyhydramnios, dystocia, torsion, respiratory distress
    Prognosis:	60% resolve within first 6 months of life

  • Hydrometrocolpos

  • Meningocele

  • Sacrococcygeal teratoma

Fetal Ascites

• ASCITES + FETAL HYDROPS

  • Immune hydrops

  • Nonimmune hydrops

• ISOLATED ASCITES

  • Urinary ascites

  • Meconium peritonitis

  • Bowel rupture

  • Ruptured ovarian cyst

  • Hydrometrocolpos

  • Glycogen storage disease

Fetal urinary tract anomalies

• Types:

  • Bilateral renal agenesis

  • Infantile polycystic kidney disease

  • Adult polycystic kidney disease

  • Multicystic dysplastic kidney

  • Ureteropelvic junction obstruction

  • Megaureter

  • Posterior urethral valves

  • Prune belly syndrome

  • Megacystis-microcolon-intestinal hypoperistalsis syndrome

  P.1008

  • Mesoblastic nephroma

  • Wilms tumor

  • Neuroblastoma

    Associated with:	chromosome abnormalities in 12% (74% trisomy, 10% deletion, 9% sex chromosome aneuploidy, 6% triploidy)
    fetal urine production:	5 mL/hr at 20 weeks MA;
    	56 mL/hr at 40 weeks MA
    bladder volume:	1 mL at 20 weeks MA;
    	36 mL at 40 weeks MA

• filling + emptying of fetal urinary bladder occurs every 10 30 (range 7 43) minutes

• increased renal parenchymal echogenicity indicates renal abnormality in 80%

• fetal hydronephrosis

  • = AP diameter of renal pelvis >5 mm at 15 20 weeks, 8 mm at 20 30 weeks, 10 mm at >30 weeks

General gynecology

Pelvic Features of Estrogen Stimulation

• increased thickness + volume of uterus

• fundocervical ratio >2

• echogenic endometrium

• appearance of ovaries NOT USEFUL (because of widely varying ovarian volumes + normal visualization of follicles at all ages)

Precocious Puberty

• = complete sexual development with secondary sex characteristics appearing <8 years of age in girls / <9 years of age in boys

• premature thelarche / adrenarche / menarche

• Terminology:

  • isosexual = secondary sex characteristics appropriate for patient's gender

  • heterosexual = secondary sex characteristics inappropriate for patient's gender

    • virilization in girls

    • feminization in boys

  • gonadotropin-dependent = true precocious puberty

  • gonadotropin-independent = pseudoprecocious puberty

Isolated Premature Adrenarche

• = pubic hair development due to action of adrenal androgens

• increased levels of adrenal androgens

• prepubertal uterus + ovaries (0.1 1 cm³)

Isolated Premature Thelarche

• = breast enlargement

• May occur without endocrine abnormalities

• prepubertal uterus + ovaries

Pseudoprecocious Puberty

• = pseudosexual PRECOCITY = PERIPHERAL PRECOCIOUS PUBERTY= incomplete precocious puberty

• = pubertal changes occurring independently of the action of pituitary gonadotropins, ie, early development of secondary sex characteristics without ovulation

• Cause:

  • Autonomous ovarian follicular cyst (most common cause)

  • Estrogen-secreting ovarian tumor:

    • eg, granulosa theca-cell tumor, gonadoblastoma, thecoma, choriocarcinoma

  • McCune-Albright syndrome

  • Adrenocortical neoplasm

  • Hypothyroidism

  • Neurofibromatosis

  • Hepatoblastoma

  • Estrogen ingestion

• low gonadotropin levels after LHRH stimulation

• high estradiol level

• low levels of FSH and LH

• normal bone age

• prepubertal uterus + ovaries

• asymmetric ovarian enlargement (one ovary 2.4 7 cm³) with macrocysts (>9 mm)

• unilateral follicular ovarian cyst characterized by internal daughter cyst

True Precocious Puberty

• = CENTRAL PRECOCIOUS PUBERTY = TRUE ISOSEXUAL PRECOCITY = complete precocious puberty

• = gonadotropin-dependent early development of gonads + secondary sex characteristics with ovulation before 8 years of age

• Cause:

  • Idiopathic activation of hypothalamic-pituitary-gonadal axis (66 80%)

  • Lesion of pituitary gland / hypothalamus:

    • eg, tuber cinereum hamartoma

  • Increased intracranial pressure:

    • eg, postmeningitis hydrocephalus

• increased levels of estrogen

• increased gonadotropin levels after LHRH stimulation

• advanced bone age

• adult-sized ovaries (1.2 12 cm³)

• dominance of corpus over cervix length

Amenorrhea

Primary Amenorrhea

• Definition:

  • no menarche by 16 years of age

  • no thelarche / adrenarche by 14 years of age

  • no menarche >3 years after adrenarche + thelarche

• Cause:

  • FEMALE ANATOMIC ANOMALIES

    • = M llerian (uterovaginal) anomalies (20%)

  • CONGENITAL DISORDERS OF SEXUAL DIFFERENTIATION

    • pure gonadal dysgenesis = Turner syndrome (33%)

      • bilateral dysfunctional / streak gonads

    • mixed gonadal dysgenesis

      • testis + streak gonad

    P.1009

    Risk:

    in 25% development of dysgerminoma / gonadoblastoma in dysgenetic gonads with Y chromosome

  • OVARIAN FAILURE / DYSFUNCTION

  • HYPOTHALAMIC / PITUITARY CAUSES (15%)

  • CONSTITUTIONAL DELAY (10%)

  • OTHERS: eg, systemic, psychiatric illness (22%)

• absent / streak gonads + infantile uterus:

  • Hypogonadotrophic hypogonadism

    • low / normal LH + FSH levels

      • hypothalamic dysfunction: hypothalamic tumor, Kallmann disease (= lack of pulsatile GnRH release), systemic illness, constitutional growth delay, extreme physical / psychological / nutritional stress (cystic fibrosis, sickle cell disease, Crohn disease), irradiation

      • pituitary dysfunction: disruption of pituitary stalk from child abuse, head trauma

  • Hypergonadotropic hypogonadism

    • = ovarian tissue fails to respond to endogenous gonadotropins

    • high LH + FSH levels

    • abnormal karyotype: Turner syndrome, XY gonadal dysgenesis

    • irradiation, chemotherapy, autoimmune disease (eg, autoimmune oophoritis)

• absent uterus:

  • Testicular feminization = male intersex = male pseudohermaphroditism (end-organ insensitivity to testosterone)

  • M llerian dysgenesis (= Mayer-Rokitansky-K ster-Hauser syndrome)

    • normal fallopian tubes + ovaries

    associated with:

    unilateral renal abnormality (50%), skeletal abnormality (12%)

• small infantile uterus:

  • Androgen-producing virilizing tumors of adolescent ovary (usually Sertoli-Leydig cell tumor)

    • unilateral adnexal mass

  • Turner syndrome

  • In utero exposure to diethylstilbestrol

• normal uterus + unilateral ovarian tumor:

  • Estrogen-producing ovarian tumor with disruption of menstrual cycle:

    • granulosa cell tumor, thecoma

• hematometrocolpos:

  • neonate = congenital uterovaginal obstruction

    • Urogenital sinus / cloacal malformation

      • pelviabdominal cystic mass with fluid-debris level in fetal US during 3rd trimester

      • renal dysplasia / obstruction

  • teenager

    • Imperforate hymen

    • Transverse vaginal septum

      • in upper vagina (45%)

      • in mid vagina (40%)

      • in lower vagina (15%)

• hematometra

  • Cervical dysgenesis

• bilateral ovarian enlargement:

  • Polycystic ovary syndrome

    • (= Stein-Leventhal syndrome): most common cause of secondary amenorrhea

Secondary Amenorrhea

• Pregnancy: most common cause in girls >9 years of age

• Polycystic ovary syndrome (main pathologic cause)

• Asherman syndrome

• All causes of primary amenorrhea

Calcifications of Female Genital Tract

• UTERUS

  • Uterine fibroid

  • Arcuate arteries

• OVARIES

  • Dermoid cyst (50%)

  • Papillary cystadenoma (psammomatous bodies)

  • Cystadenocarcinoma

  • Hemangiopericytoma

  • Gonadoblastoma

  • Chronic ovarian torsion

  • Pseudomyxoma peritonei

• FALLOPIAN TUBES

  • Tuberculous salpingitis

• PLACENTA

• LITHOPEDION

Psammoma Bodies in Tumors

• Papillary serous cystadenoma / cystadenocarcinoma

• Mucinous carcinoma of colon

• Papillary thyroid cancer

• Meningioma

Free Fluid in Cul-de-sac

• Follicular rupture

• Ovulation

• Ectopic pregnancy

• S/P culdocentesis

• Ovarian neoplasm

• Pelvic inflammatory disease

Pelvic mass

Frequency of Pelvic Masses

Cystic Pelvic Masses

• CYSTIC ADNEXAL MASS

• EXTRAADNEXAL CYSTIC MASS

  • Peritoneal inclusion cyst

  • Mesenteric cyst

  • Lymphocele

  • Bladder diverticulum

  P.1010

  • Ectopic gestation

  • Fluid-distended bowel

  • Loculated pelvic abscess: appendiceal, diverticular, postoperative, Crohn disease, tuberculous, pelvic actinomycosis

Complex Pelvic Mass

• Cystadenoma / cystadenocarcinoma

• Hemorrhagic cyst

• Endometrioma

• Ectopic pregnancy

• Teratoma (dermoid)

• Abscess (from adjacent appendicitis, etc.)

• Hematoma in pelvis

Solid Pelvic Masses

• Pedunculated myoma (most common)

• Fibroma

• Adenofibroma

• Thecoma

• Brenner tumor

Fatty Pelvic Mass

• UTERUS

  • Lipoleiomyoma

  • Fibromyolipoma

• OVARY

  • Benign cystic ovarian teratoma

  • Malignant degeneration of cystic teratoma

  • Nonteratomatous lipomatous ovarian tumor

• PELVIS

  • Benign pelvic lipoma

  • Liposarcoma

  • Lipoblastic lymphadenopathy

Extrauterine Pelvic Masses

• Solid adnexal mass

• Metastatic disease

• Lymphoma

• Pelvic kidney

• Rectosigmoid carcinoma

• Bladder carcinoma

• Retroperitoneal tumor / fibrosis

• Intraperitoneal fat

• Vascular mass / malformation

• Hematoma

• Bowel

Pelvic Pain in Pediatric Age Group

• Ovarian torsion

  • of normal ovary

    Cause:

    excessive mobility of ovary in childhood

  • with ovarian mass:

    • functional cyst (60%)

    • neoplasm (40%):

      • benign mature teratoma (66%)

      • malignancy (33%): germ cell tumor (60 75%), epithelial tumor (10 20%), stromal tumor (10%)

• Hemorrhagic ovarian cyst

• Pelvic inflammatory disease

• Ectopic pregnancy

Adnexa

Adnexal Masses

• CYSTIC

  • Physiologic ovarian cyst:

    Graafian follicle:	at midcycle <25 mm
    Corpus luteum:	after midcycle <15 mm

  • Functional / retention cyst

  • Endometrioma

  • Tuboovarian abscess

  • Dermoid cyst

  • Ectopic pregnancy

  • Paraovarian cyst / cystadenoma

  • Serous / mucinous ovarian tumor

  • Hyperstimulation cysts

  • Peritoneal inclusion cyst

  • Massive ovarian edema

  • Hydrosalpinx

• SOLID

  • Ovarian tumor

  • Ovarian torsion

  • Oophoritis

  • Polycystic ovaries

  • Fallopian tube carcinoma

  • Pedunculated fibroid

Hemorrhagic Adnexal Lesion

• Endometriosis

• Hemorrhagic ovarian cyst

• Hemorrhagic foci of adenomyosis

• Hematosalpinx

Low-intensity Adnexal Lesion on T1WI

• Fibroma

• Fibrothecoma

• Cystadenofibroma

• Brenner tumor

• Wall of chronic pelvic abscess

• Pedunculated leiomyoma

High-intensity Adnexal Lesion on T1WI

• Endometrioma

  • frequently multilocular + bilateral

  • shading (= signal loss) on T2WI

• Dermoid

  • chemical shift artifact

  • signal drop-out after fat suppression

• Mucinous cystic neoplasm

  • signal intensity less than fat / blood

• Hemorrhagic cyst

  • unilocular

  • no shading

  • resolution with time

• Ovarian carcinoma

  • solid components, septations

  • large size

Adnexal Mass in Pregnancy

P.1011

• RESOLVING BY 14 16 WEEKS EGA

  • Corpus luteum cyst

  • Theca lutein cyst

• PERSISTENT ADNEXAL MASS

  • Benign

    • correctly diagnosed by US: 95% of dermoids, 80% of endometriomas, 71% of simple cysts

  • Malignant (0.1 0.8%)

Ovarian Tumors

• pressure symptoms: abdominal discomfort, vomiting, flatulence, dyspnea

• acute pain from torsion, hemorrhage

• chronic pain from slowly enlarging mass, impaction, adhesions

• menstrual irregularity

• Radiologic guidelines:

  • Imaging features of ovarian neoplasms virtually never allow a specific diagnosis. Regardless of further differentiation patients always undergo surgery!

  • Signs suggestive of benignancy:

    • unilocularity of cyst

    • thin wall <3 mm

    • minimal septations

    • absence of papillary projection

  • Signs suggestive of malignancy:

    • solid nonfatty nonfibrous tissue (most powerful predictor of malignancy!)

    • many solid-tissue elements in a complex lesion

    • wall thickness >3 mm

    • inner wall irregularities / papillary projections

    • thick septations >3 mm

    • increased echogenicity within a cyst

      Age:	13% of neoplasms malignant in premenopause; 45% of neoplasms malignant in postmenopause
      Cx:	(1) Torsion (in 10 20%)
      	(2)Rupture (rare)
      (3) Infection

• Classification:

  • 75% of ovarian neoplasms are benign

  • 21% of ovarian neoplasms are malignant

  • 4% of ovarian neoplasms are borderline malignant

Tumors of Surface Epithelium (60 70%)

• = 85 95% of all ovarian cancers

• propensity for early peritoneal + lymphatic spread

• peritoneal studding

• omental cake

• perihepatic diaphragmatic implants

  Subclassification of Ovarian Tumors

  	Benign	Borderline	Malignant
  [all types combined	75%	4%	21%]
  Serous	60%	15%	25%
  Mucinous	80%	10%	10%
  Endometrioid	~0%	~0%	~100%
  Clear cell	~0%	~0%	~100%
  Undifferentiated	0%	0%	100%

  • Serous ovarian tumor (50%)

  • Endometrioid tumor (15 30%)

  • Mucinous ovarian tumor (15%)

  • Clear cell adenocarcinoma (5%)

  • Undifferentiated carcinoma (<5%)

  • Brenner tumor (2.5%)

  • Cystadenofibroma

Germ Cell Tumors (15 30%)

• 40% of germ cell tumors are malignant

• benign (10%)

  • Dermoid cyst = mature teratoma (most common)

• malignant

  • account for 75% of ovarian cancers seen in 1st 2nd decade of life; <5% of all ovarian tumors; in order of frequency:

    • Dysgerminoma (1.9%)

    • Immature teratoma (1.3%)

    • Endodermal sinus tumor (1%)

    • Malignant mixed germ cell tumor (0.7%)

    • Embryonal carcinoma (0.1%)

    • Choriocarcinoma (0.1%)

Sex Cord-Stromal Tumors (5 8%)

• usually have more than one cell type + arise from two groups of cells:

• primitive sex cord cells, which form from the coelomic epithelium (= primordial peritoneum) differentiate into granulosa cells + Sertoli cells

• stromal cells (fibroblasts, theca cells, Leydig cells) derive from the genital ridge mesonephros mesenchyma

• broad range of ages

• most present at stage I with good prognosis

• absent tumor markers

• Often manifest with tumor-mediated hormonal effects

• NO papillary projections

• lack of fat + calcifications

  • hyperestrogenic tumors: granulosa cell tumor, thecoma, stromal luteoma

  • virilizing tumors: Sertoli-Leydig cell tumor, steroid cell tumor (Sertoli cell tumor, Leydig cell tumor)

• Granulosa-stromal cell tumors

  1. Juvenile granulosa cell tumor	multicystic
  2. Adult granulosa cell tumor	solid
  3. Thecoma	solid
  4. Fibroma	solid
  5. Fibrosarcoma
  6. Sclerosing stromal tumor

• Sertoli-stromal cell tumors

  1. Sertoli-Leydig tumor	solid
  2. Sertoli cell = arrhenoblastoma	solid
  3. Leydig cell

• Steroid cell tumors = lipid cell tumors

  • Stromal luteoma

  • Leydig cell tumor = hilus cell tumor

  • Steroid cell tumor, not otherwise specified

• Other

  • Gynandroblastoma

  • Sex cord tumor with annular tubules

    • associated with Peutz-Jeghers syndrome (30% of all tumors with annular tubules)

  P.1012

  • Sclerosing stromal tumor

• SECONDARY OVARIAN TUMORS (5%)

  • Metastases from: pelvic organs, upper GI tract, breast, bronchus, reticuloendothelial tumors, leukemia

• Terminology:

Solid Ovarian Tumor

• Fibroma

• Thecoma

• Granulosa cell tumor

• Sertoli-Leydig cell tumor

• Brenner tumor

• Sarcoma

• Dysgerminoma

• Endodermal sinus tumor

• Teratoma

• Metastasis

• Endometrioma

• Massive ovarian edema

• Leiomyoma

Proximal Fallopian Tube Obstruction

• Extensive fibrosis / salpingitis isthmica nodosa (40%)

• Amorphous debris / minimal adhesions (40%)

• Tubal spasm (20%)

Uterus

Prepubertal Vaginal Bleeding

• Vaginal foreign body

  Incidence:

  in 18% of children with vaginal bleeding + discharge; in 50% of children with vaginal bleeding + no discharge

• Vaginal rhabdomyosarcoma

• Precocious puberty

• Hemangioma

• Vascular malformation

Postmenopausal Vaginal Bleeding

• Endometrial atrophy (in 60 75%)

  • thin atrophic endometrium is prone to superficial ulceration

  • in 75% endometrial thickness <4 5 mm

    • Patient may forego endometrial biopsy!

  • in 25% endometrial thickness of 6 15 mm

• Endometrial hyperplasia

• Endometrial polyp

• Submucosal fibroid

  • hypoechoic mass with an overlying normal echogenic endometrium

  • acoustic attenuation

  • prolapse into endometrial cavity

    Rx:	can be removed at hysteroscopy if >50% of mass projects into endometrial cavity

• Adenomyoma

  • indistinguishable from submucosal fibroid

• Endometrial carcinoma (in 7 20%)

• Estrogen withdrawal

• Optimal time of imaging:

  • immediately after cessation of bleeding when endometrium is presumed to be thinnest

Diffusely Thickened Irregular Endometrium

• Normal endometrial thickness: see Anatomy

• Sensitivity for detection of endometrial abnormalities: 80% for transvaginal US; 30% for endometrial biopsy

• Endometrial hyperplasia

  Age:	peri- / postmenopausal women
  Cause:	prolonged endogenous / exogenous unopposed estrogen stimulation

  • focal / diffuse endometrial thickening >5 6 mm

  • formation of polyps of up to 5 cm

  • Types:

    • glandular-cystic hyperplasia (most common)

      Histo:

      dilated glands lined by tall columnar / cuboidal epithelium

      • small cysts within evenly echogenic endometrium

      Prognosis:

      NO premalignant condition

    • adenomatous hyperplasia

      • endometrium with irregular hypoechoic areas

      Prognosis:

      precursor of endometrial cancer

• Secretory endometrium

  • Improve timing of the examination!

• Endometrial cancer

• Endometritis

• Tamoxifen-related endometrial changes

  • = nonsteroidal antiestrogen in breast acts as a weak estrogen agonist causing proliferative effects on the endometrium

    Increased prevalence of:	endometrial hyperplasia, polyps, carcinoma
    	50% of women treated with tamoxifen will develop endometrial abnormalities within 6 36 months

  • Histo:

    • endometrial thickness increased to 10.4 mm; 4.2 mm in control subjects

    • polyps (36%); 10% in control subjects

    • atrophic changes (28%); 87% in control group

  • hemorrhage (requires further evaluation)

  • endometrial thickening >5 9 mm:

    • endometrial hyperplasia

    • endometrial polyp

    • subendometrial cystic changes (= glandular distension within a polyp / reactivated adenomyosis within inner myometrium)

  • MR:

    • endometrium-myometrium interface (due to endometrial atrophy / proliferative changes):

      • homogeneously hyperintense on T2WI

      • signal void + enhancement on T1WI

    • polyps:

      • heterogeneous intensity on T2WI

      P.1013

      • laticelike enhancement traversing endometrial canal on T1WI

Focally Thickened Endometrium

• Endometrial polyp

  • = focal hyperplasia of stratum basale; in 20% multiple

    Age:	mainly 30 60 years
    Histo:	projections of endometrial glands + stroma into uterine cavity

    • hyperplastic polyp resembling endometrial hyperplasia

    • functional polyp resembling surrounding endometrium (least frequent)

    • atrophic polyp

    Frequently associated with:

    tamoxifen therapy

  • US:

    • sessile broad-based / pedunculated well-defined smooth hyperechoic homogeneous intracavitary mass (79%) / variable echogenicity (best seen on sonohysterography):

      • cystic spaces (in 59%) due to enlarged dilated glands filled with proteinaceous fluid

      • heterogeneous texture suggests infarction, inflammation, hemorrhage

      • vessel visualized within stalk on color Doppler

        Malignant transformation:

        in 0.4 3.7%

• Primary carcinoma of the endometrium

  Risk factors:	exposure to unopposed estrogen, obesity, nulliparity, hypertension, diabetes
  Location:	predominantly in uterine fundus; 24% in isthmic portion)

  • 10% cancer rate with endometrial thickness of 6 15 mm

  • 50% cancer rate with endometrial thickness of >15 mm

  • irregular heterogeneous endometrium >5 mm in thickness

  • focal / diffuse endometrial thickening (mean thickness of 18.2 mm)

  • irregular poorly defined endometrial-myometrial interface

  • increased echogenicity in myometrium (= invasive endometrial cancer)

  • Doppler waveforms with resistive index <0.7 suggest malignancy

• Metastatic carcinoma:

  • ovary, cervix, fallopian tube, leukemia

• Hydatidiform mole

  • echogenic mass with irregular sonolucent areas

• Incomplete abortion

• Submucosal leiomyoma

  • mass hypo- / hyperechoic relative to myometrium

  • wide attachment to myometrium

  • intracavitary margin outlined by echogenic rim of endometrium

  • acoustic attenuation

    Rx:	hysteroscopic removal if >50% of mass projects into endometrial cavity

• Focal adenomyoma

  • hypoechoic mass with an overlying echogenic endometrium

    DDx:	indistinguishable from submucosal fibroid

• Intrauterine synechiae

  • echogenic bands extending from one endometrial surface to the other

Fluid Collection within Endometrial Canal

• PREMENOPAUSAL

  • Infection: endometritis, pyometrium

  • Congenital obstructive lesion: imperforate hymen, vaginal septum, vaginal / cervical atresia

  • Acquired obstructive lesion: cervical stenosis (following instrumentation / cone biopsy / radiation), cervical carcinoma

  • Spontaneous hematometra in bleeding disorders

  • Pregnancy: intrauterine, ectopic, incomplete abortion

  • Endometrial cancer

  • Endometrial polyp, submucosal fibroid

  • Functional: during menstruation

• POSTMENOPAUSAL

  • Endometrial / cervical cancer

  • Cervical stenosis

  • Normal if amount small

Endometrial Cysts

• Endometrial cystic atrophy

  Histo:

  cystically dilated atrophic glands lined by single layer of flattened / low cuboidal epithelium

  • very thin endometrium of <4 5 mm

• Endometrial cystic hyperplasia

Diffuse Uterine Enlargement

• Diffuse leiomyomatosis

• Adenomyosis

• Endometrial carcinoma (15%)

Uterine Masses

• BENIGN

  • Uterine fibroids (99%)

  • Pyometra

  • Hemato- / hydrocolpos

  • Transient uterine contraction (during pregnancy)

  • Bicornuate uterus

  • Adenomyosis

  • Intrauterine pregnancy

  • Lipoleiomyoma (<50 cases in world literature)

• MALIGNANT

  • Cervical carcinoma

  • Endometrial carcinoma

  • Leiomyosarcoma

  • Invasive trophoblastic disease

Cervical Mass

• Fibroid

• Carcinoma

• Endometrial polyp

• Nabothian cyst (= retention cyst related to chronic cervicitis)

P.1014

Fundic Depression on HSG

• with normal outer contour

  • Septate uterus

  • Arcuate uterus

• with abnormal outer contour

  • Bicornuate uterus

  • Fundal myoma

Filling Defect on HSG

• Synechia

• Endometrial polyp

• Submucosal myoma

• Uterine folds = parallel to long axis of uterus

• Air bubbles

Abnormal Uterine Contour on HSG

• Submucosal myoma

• Adenomyosis

• Trauma (cesarian section, myomectomy)

Cervical Stenosis

• = obliteration + obstruction of endocervical canal

  • CONGENITAL

    • Transverse vaginal septum in uterus didelphys

    • Congenital absence of cervix

  • ACQUIRED

    • Cervical carcinoma (postmenopausal)

    • Endometrial cancer (premenopausal)

    • S/P radiation treatment

    • S/P endocervical curettage

• distension of endometrial cavity by secretions + blood products;

Postpartum Hemorrhage

• Uterine atony

  • hemorrhage in immediate postpartum period

  • normal uterus

• Retained products of conception

  • hemorrhage several days after delivery

  • echogenic intracavitary mass attached to endometrium

  • high-velocity flow >21 cm/sec of low resistance (supplying residual trophoblastic tissue)

  • calcification of retained products (late finding)

Vagina

Vaginal Cyst

• Gartner duct cyst

• Bartholin gland cyst

  • = female homologue of male Cowper glands

    Location:

    posterolateral portion of lower vagina

• Paramesonephric / m llerian duct cyst

  • = aberrant remnant of paramesonephric duct

    Location:

    anterior wall of vagina near cervix

• Epithelial inclusion cyst

  • = arise from urogenital sinus

    Histo:

    lined by transitional epithelium containing thick caseous material

Vaginal Fistula

• Enterovaginal fistula:

  • rectovaginal: incomplete healing of perineal laceration from obstetric trauma, radiation therapy

  • anovaginal: inflammatory bowel disease (10% of patients with Crohn disease)

  • colovaginal: diverticulitis

• Vesicovaginal fistula:

  • hysterectomy, radiation therapy

• Ureterovaginal fistula: vaginal hysterectomy

Vaginal & Paravaginal Neoplasm

• PRIMARY

  • Cavernous hemangioma of vulva

  • Pedunculated submucosal leiomyoma prolapsed into vagina

  • Adenoid cystic carcinoma of Bartholin gland

  • Vaginal carcinoma

    • squamous cell carcinoma (90%)

    • adenocarcinoma (3%)

  • Rhabdomyosarcoma

• SECONDARY (80% of all vaginal tumors)

  • direct extension from bladder, rectum, cervix, uterus

Gas in genital tract

• UTERUS

  • Endometritis

  • Superinfection of leiomyoma: more common in submucosal leiomyoma (insufficient blood supply)

  • Bacterial metabolism of necrotic neoplastic tissue

  • Fistula to GI tract: uterine cancer

  • Pyometra secondary to obstruction by cervical cancer

  • Gas gangrene: due to clostridial infection from septic abortion

• OVARY

  • Superinfected ovarian neoplasm

• VAGINA

  • Vaginitis emphysematosa

    • = nonbacterial self-limiting process mostly occurring during pregnancy characterized by numerous gas-filled spaces in submucosa of vagina + exocervix

P.1015

Anatomy and Physiology of Female Reproductive System

Human chorionic gonadotropin

= hCG = glycoprotein elaborated by placental trophoblastic cells beginning the 8th day after conception

Immunologic Pregnancy Test

• = indirect agglutination test for hCG in urine; cross-reaction with other hormones / medications possible

• Becomes positive at 5 weeks MA

Radioimmunoassay (RIA) Pregnancy Test

• = measures beta subunit of hCG in serum with a sensitivity as low as 1 2 mIU/mL

• Serum -hCG becomes positive at 3 weeks MA / 7 10 days following conception!

• Standards:

  • (1) Second International Standard (SIS)

  • (2) International Reference Preparation (IRP)

  • (3) Third International Standard (TIS)

  • 1 mIU/mL (SIS) = 2 mIU/mL (IRP) = 2 mIU/mL (TIS)

  • 1 ng/mL = 5 6 mIU/mL (SIS)

    = 10 12 mIU/mL (IRP or TIS)

    Variations of lab values of up to 50% can occur among different laboratories!

  • 6 15% between-run precision!

Anatomy of gestation

Choriodecidua

Chorion

=trophoblast + fetal mesenchyme with villous stems protruding into decidua; provides nutrition for developing embryo

• chorion frondosum = part adjacent to decidua basalis, forms primordial placenta

• chorion laeve = smooth portion of chorion with atrophied villi

• chorionic plate = amnionic membrane covering the chorionic plate of the placenta

1 7 11 rule :

Decidua

• decidua basalis = between chorion frondosum + myometrium

• decidua capsularis = portion protruding into uterine cavity

• decidua parietalis = decidua vera = portion lining the uterine cavity elsewhere

Gestational Sac (GS)

• Arises from blastocyst, which implants into secretory endometrium 6 9 days after ovulation (= 20 23 days of MA), surrounded by echogenic trophoblast

• GS measures 0.1 mm at time of implantation

• intradecidual sign (earliest sign) = intrauterine fluid collection corresponding to gestational sac completely embedded within decidua (48% sensitive, 66% specific, 45% accurate) at <5 weeks GA

• double decidual sac sign (DDS) [most useful >5 weeks GA] = 2 concentric hyperechoic rings surrounding a portion of the gestational sac:

  • outer echogenic ring (= decidua parietalis)

  • interposed hypoechoic line (apposed endometrial walls)

  • inner echogenic ring (= decidua capsularis)

  • DDS present with a mean sac diameter of 10 mm (= 40 days GA)

  • A double decidual sac sign correlates with the presence of pregnancy in 98%!

• GS surrounded by endometrial thickening >12 mm

• continuous hyperechoic inner rim >2 mm thick

• spherical / ovoid shape without angulations

• mean sac diameter grows 1.13 (range 0.71 1.75) mm/day

  Anatomy of Gestation

P.1016

Gestational Sac Size

• linear growth: 10 mm by 5th week MA

  60 mm by 12th week MA

• fills chorionic cavity by 11th 12th weeks MA

Visualization of Gestational Sac

• Earliest visualization: mean sac diameter of 2 3 mm

• A. GS VISUALIZATION VERSUS -hCG LEVEL (2^nd International Standard):

  • on transabdominal scan:

    • in 100% with -hCG levels of >1,800 IU/L

  • on transvaginal scan:

    in	20% with -hCG levels of	<500 IU/L
    in	80% with -hCG levels of	500 1,000 IU/L
    in	100% with -hCG levels of	>1,000 IU/L

• B. GS VISUALIZATION VERSUS MENSTRUAL AGE

  5.0 1 weeks	= 10 mm
  5.5 1 weeks	= 13 mm
  6.0 1 weeks	= 17 mm
  6.5 1 week	= 20 mm

Secondary Yolk Sac

• = rounded sonolucent structure (outside amniotic cavity) within chorionic sac (= extracoelomic cavity) connected to umbilicus via a narrow stalk; formed by proliferation of endodermal cells; part of yolk sac is incorporated into fetal gut; the rest persists as a sac connected to the fetus by the vitelline duct

• Function:

  • transfer of nutrients from trophoblast to embryo prior to functioning placental circulation

  • early formation of blood vessels + blood precursors on sac wall

  • formation of primitive gut

  • source of primordial germ cells

• Time of formation: at around 28 days MA

• Mean size:

  1.0 mm by 4.7 weeks MA; 2.0 mm by 5.6 weeks MA; 3.0 mm by 7.1 weeks MA; 4.0 (2.2 5.3) mm by 10 weeks MA; disappears around 12 weeks MA

  First visible structure within gestational sac

• Definite visualization on transvaginal scan:

  at 5.5 weeks MA

  No Caption Available. earliest detection at 5 weeks GA, embryo 2 mm in length Vitelline Duct 8 weeks GA Early Coiled Umbilical Cord 9 weeks GA

  in GS with a mean sac diameter of 8 mm

• Definite visualization on transabdominal scan:

  in GS with a mean diameter of 20 mm

  at a gestational age of 7 weeks MA

Embryo

• Developmental stages:

  Preembryonic period:	2nd 4th week MA
  Trilaminar embryonic disk:	during 5th week MA
  Embryonic period:	6th 10th week MA
  Physiologic umbilical herniation:	8th 12th week MA
  Fetal period:	beginning at 11th week MA

• Average growth rate:

  0.7 mm per day / 1.5 mm every 2 days;

  curvilinear growth from 7 mm at 6.3 weeks MA to 50 mm at 12.0 weeks MA

• Earliest visualization (on endovaginal scan):

  at 5.4 weeks MA at CRL of 1.2 mm

VISUALIZATION OF EMBRYO VERSUS GS

• on transabdominal scan

  100% visualization if gestational sac 27 mm

• on transvaginal scan

  100% visualization if gestational sac 12 mm

  Transvaginal scan not necessary if on transabdominal scan gestational sac >27 mm without evidence of embryo!

• Failed pregnancy:

  nonvisualization of embryo with mean gestational sac size of 18 mm

Cardiac Activity of Embryo

• Heart begins to contract at a CRL of 1.5 3 mm = 22 days GA = 36 days MA

  • Definite visualization on endovaginal scan:

    • at 46 days GA

    • mean sac diameter of 16 mm

    • CRL 5 mm CRL = 6.2 weeks

  • Definite visualization on transabdominal scan:

    • at 55 days GA

    • mean sac diameter of 25 mm

  • Rate:

    at 5-6 weeks GA	101 bpm
    at 8-9 weeks GA	143 bpm

P.1017

Amnionic Membrane

• = curvilinear echogenic line within chorionic sac; fills chorionic cavity by 11 12 weeks MA;

• Fusion:

  • fuses with chorionic membrane at approximately 16 weeks MA to form the chorionic plate

  • incomplete fusion with chorion frequent (DDx: subchorionic hemorrhage, twin abortion, coexistent with limb-body wall complex)

Umbilical Cord

• Embryology:

  • cord forms between 5th and 12th postmenstrual week with contributions from body stalk, omphalo-mesenteric or vitelline duct, yolk sac, allantois

  • junction of the amnion with ventral surface of embryo will form umbilicus

  • midgut undergoes physiologic herniation into the base of the umbilical cord 7 12 postmenstrual weeks

  • cord grows until end of 2nd trimester: average diameter of 17 mm, length of 50 60 cm

• Anatomy:

  • 1 2 cm in diameter

  • two umbilical arteries = branches of the two internal iliac arteries

  • one umbilical vein (remains after regression of right umbilical vein in early embryonic period)

  • Wharton jelly = compressible matrix of cord

  • covered by amnion

  • spiraling of cord with 0 40 twists established by 9 weeks

Placental Grading

• according to echo appearance of basal zone, chorionic plate, placental substance

  Premature placental calcifications are associated with cigarette smoking, hypertension, IUGR!

  Not considered useful because placental grading is imprecise for fetal dating or for fetal lung maturity!

• GRADE 0

  homogeneous placenta + straight line of chorionic plate

  Time:

  <30 weeks MA

• GRADE 1

  undulated chorionic plate + scattered bright placental echoes

  Time:

  seen at any time during pregnancy; in 40% at term in 68% L/S ratio >2.0

• GRADE 2

  linear bright echoes parallel to basal plate

  confluent stippled echoes within placenta indentations of chorionic plate

  Time:

  rarely seen in gestations <32 weeks MA; seen in 40% at term

  in 87% L/S ratio >2.0

• GRADE 3

  calcified intercotyledonary septa, often surrounding sonolucent center

  Time:

  rarely seen in gestations <34 weeks MA; in 15 20% at term

  in 100% L/S ratio >2.0 (= strongly correlated with lung maturity)

Premature Placental Senescence

= grade 3 placenta seen in gestation <34 weeks MA

In 50% suggestive of maternal hypertension / IUGR

Uteroplacental Circulation

By 20 weeks MA trophoblast invades maternal vessels and transforms spiral arteries into distended tortuous vessels = uteroplacental arteries

Histo:

• in the decidual portion of spiral arteries: proliferating trophoblast from anchoring villi invades lumen of spiral arteries + partially replaces endothelium

• in the myometrial portion of spiral arteries: disintegration of smooth muscle elements (loss of elastic lamina) leads to easily distensible vascular system of low resistance

Uterine Blood Volume Flow

• 50 mL/min shortly after conception

• 500 900 mL/min by term

  Intervillous blood flow:

  140 53 mL/min (by Xe-133 washout)

Umbilical Artery Doppler

Variables affecting Doppler measurements:

• site of Doppler (close to placenta preferred), fetal heart rate, fetal breathing, drugs (ritodrine hydrochloride decreases S/D ratio)

• degree of diastolic flow increases as gestation progresses

• S/D ratio between 3.3 and 4.3 at 20 weeks

• S/D ratio between 1.7 and 2.4 at term

• highly turbulent flow

IUGR Lesions

= narrowing of vascular lumen through

• thrombosis of decidual segments of uteroplacental arteries

• failure of development of myometrial segments of uteroplacental arteries

Fetal mensuration

US is more reliable than LMP / physical examination!

Ultrasound Milestones

Accuracy: 0.5 week

Fetal Age

• = GESTATIONAL AGE (GA) = MENSTRUAL AGE (MA)

• = age of pregnancy based on woman's regular last menstrual period (LMP) projecting the estimated date of confinement (EDC) at 40 weeks

  Note the inaccurate clinical usage of gestational age, which strictly speaking refers to the true age of the pregnancy counting from the day of conception, whereas menstrual age refers to the true age of the pregnancy + approximately 2 weeks counting from the first day of the last menstruation!

  P.1018

  On subsequent scans GA = GA assigned at 1st ultrasound + number of intervening weeks!

• ACCURACY OF CLINICAL ASSESSMENT

  menstrual history	2 3 weeks
  1st-trimester exam	2 weeks
  fundal height	4 weeks

Gestational Sac (GS)

• = average of 3 diameters (craniocaudad, AP, TRV) of anechoic space within sac walls

  Used for dating between 6 and 12 weeks MA (identified as early as 5 weeks MA on transabdominal scan)

• EGA [in wks] = (GS [in mm] + 25.43) 7.02

Early Embryonic Size

• = length of embryo <25 mm on transvaginal scan performed at <11 weeks MA

• Gestational age (days) = embryonic size (mm) + 42

Crown-Rump Length (CRL)

• = length of fetus; useful up to 12 weeks MA (usually identified by 7 weeks MA on transabdominal scan)

Biparietal Diameter (BPD)

• = measured from leading edge to leading edge of calvarial table at widest transaxial plane of skull = level of thalami + cavum septi pellucidi + sylvian fissures with middle cerebral arteries

  Excellent means of estimating GA in 2^nd trimester >12 weeks MA

• Accuracy:

  2 mm for between occasion error

  Most accurate for dating if combined with HC, AC, FL provided body ratios are normal!

  Less reliable for dating in 3^rd trimester because of increasing biologic variability!

  Accuracy of Biometry (95% confidence range)

  Stage	Based on	Accuracy [weeks]
  1st trimester
  5 6 weeks	US milestones	0.5
  6 13 weeks	CRL	0.7
  2nd trimester
  14 20 weeks	cBPD / HC	1.2
  	BPD / FL	1.4
  20 26 weeks	cBPD / HC	1.9
  	BPD / FL	2.1 2.5
  3rd trimester
  26 32 weeks	cBPD / HC / FL	3.1
  	FL	3.1
  32 42 weeks	cBPD / HC / FL	3.5
  	FL	3.5

Discordant Estimated Date of Confinement (EDC) by LMP and BPD

• Methodological error in measurement

  • wrong axial section

  • cranial compression (multiple gestation, breech presentation, oligohydramnios, dolichocephaly)

• Erroneous LMP

  • other measurements (AC, FL) correlate with BPD

• Abnormal head growth

  • BPD less than AC:

    microcephaly, fetal macrosomia

  • BPD more than AC:

    intracranial abnormality, asymmetric IUGR

Cephalic Index (CI)

= BPD / OFD; measurements of BPD and occipitofrontal diameter (OFD) are both taken from outer to outer edge of calvarium

Confirms appropriate use of BPD if ratio is between 0.70 and 0.86 (2 SD)

Corrected BPD (cBPD)

= BPD and OFD are used to adjust for variations in head shape

Head Circumference (HC)

Used if ratio of BPD/OFD outside 0.70 0.86

Abdominal Circumference (AC)

• = measured at level of vascular junction of umbilical vein with left portal vein ( hockey-stick appearance) where it is equidistant from the lateral walls in a plane perpendicular to long axis of fetus; measured from outer edge to outer edge of soft tissues

  Allows evaluation of head-to-body disproportion

  Better predictor of fetal weight than BPD

Femur Length (FL)

• = measurement of ossified femoral diaphysis

Thoracic Circumference (TC)

• = measured in axial plane of chest, which includes four-chamber view of heart without inclusion of SQ tissue

  Linear growth between 16 and 40 weeks similar to AC

P.1019

Estimated Fetal Weight (EFW)

• based on measurements of head size (BPD / HC), abdominal size (AD / AC), and femur length (FL)

• Accuracy:

  body part used	95% confidence range
  abdomen	22%
  head + abdomen	17 20%
  head + abdomen + femur	15%

Appearance of Epiphyseal Bone Centers

in 95% of all cases

• distal femoral epiphysis (DFE): >33 weeks GA

• distal femoral epiphysis (DFE) >5 mm: >35 weeks

• proximal tibial epiphysis (PTE): >35 weeks GA

• proximal humeral epiphysis (PHE): >38 weeks GA

CNS Ventricles

Diameter of Cisterna Magna

measured from inner margin of occiput to vermis cerebelli: 2 10 mm

Assessment of fetal well-being

Amniotic Fluid Index

= sum of vertical depths of largest clear amniotic fluid pockets in the 4 uterine quadrants measured in mm

Biophysical Profile (Platt and Manning) = BPP

= in utero Apgar score = assessment of fetal well-being

A. ACUTE BIOPHYSICAL VARIABLES

Subject to rhythmic variation coincident with sleep-wake cycle!

• Fetal breathing movement (FBM):

  1 episode of chest + abdominal wall movement for a period lasting 30 seconds (time is arbitrary to avoid confusion with general body movements / maternal respiration)

  stimulated by:	glucose, catecholamine, caffeine, prostaglandin synthetase inhibitor
  suppressed by:	barbiturates, benzodiazepine, labor, hypoxia, asphyxia, prostaglandin E2

• Fetal body movement:

  3 discrete movements of limbs / trunk

  influenced by:

  glucose, gestational age, time of day, maternal drugs, intrinsic rhythm, labor

• Fetal tone

  • upper + lower limbs usually fully flexed with head on chest; least sensitive test parameter

    1 episode of opening + closing of hand / extension + flexion of limb

B. CHRONIC FETAL CONDITION

• 4. Amniotic fluid volume

  at least one pocket 2 cm in vertical diameter in two perpendicular planes

  Avoid inclusion of loops of cord!

BPP Score

The probability of fetal death within a week of a BPP score of 8/8 is 1:1,000!

Stress Tests

Nonstress Test (NST)

• Test needed in less than 5% of cases!

• reactive fetal heart rate tracing (normal) = at least 4 fetal heart accelerations (>15 bpm over baseline lasting >15 seconds) in a 20-minute period subsequent to fetal movement >34 weeks GA

• nonreactive (abnormal) fetal heart rate tracing = absence of acceleration in a continuous 40-minute observation period

Contraction Stress Test (CST)

• = external monitoring after injection of oxytocin / maternal breast stimulation

  >3 uterine contractions in 10-minute period

Results of Biophysical Profile Score (including NST for a maximum of 10 points)

P.1020

Invasive fetal assessment

Amniocentesis

• Indications:

  • Inadequate sonographic fetal anatomic survey due to fetal position / maternal body habitus

  • Equivocal sonographic findings (eg, abnormal posterior fossa but spinal defect not seen)

  • Experienced sonographer not available

  • Nonlethal anomaly detected on level I sonogram for which karyotype testing is appropriate

• Risk: fetal loss rate generally quoted as 1:200 (0.5%)

  • FETAL RISK

    • Spontaneous abortion (0.3 1.5%)

    • Amniotic fluid leak

    • Chorioamnionitis

    • Fetal injury: skin dimple, limb gangrene, porencephalic cyst, hemothorax, spleen laceration, orthopedic abnormality, amniotic band syndrome

  • MATERNAL RISK (rare)

    • Bowel perforation

    • Hemorrhage

    • Isoimmunization

Diagnostic Amniocentesis

• Genetic studies: karyotype, DNA analysis, biochemical assay

  Timing: early (11 15 weeks), late (15 18 weeks)

• Neural tube defect: -fetoprotein, acetylcholinesterase

• Isoimmunization: -OD 450

• Fetal lung maturity

• Intraamniotic infection

• Confirmation of ruptured membranes

Advantage over CVS:

• Error rate (<1% versus 2%)

• Culture failure rate (0.6% versus 2.2%)

• Fetal loss rate (0.6 0.8% less)

Therapeutic Amniocentesis

• Polyhydramnios

• Twin-twin transfusion syndrome

  Technique:

  avoid fetus, placenta, umbilical cord, uterine contraction, fibroid, large uterine vessel

  use continuous ultrasound guidance

  inject 2 5 mL of indigo carmine dye in first sac of twin (colorless fluid assures that second sac has been entered)

Chorionic Villus Sampling (CVS)

• = aspiration of cells from chorion frondosum for genetic studies (karyotype, DNA analysis, biochemical assay)

  Transabdominal CVS for rapid karyotyping in 2nd + 3rd trimester = placental biopsy

• Advantage: >2 weeks earlier results compared with amniocentesis

• Timing: 9 11 weeks

• Approach:

  • transcervical route = catheter introduced through cervix into chorion frondosum, easier for posterior placenta; contamination by cervical flora possible

    CONTRAINDICATED in cervical infections!

  • transabdominal route = 20 22-gauge needle inserted from anterior abdominal wall; easier for anterior / fundal placenta; sterile technique

• Chromosome analysis:

  • direct preparation = analysis of cytotrophoblasts (may have different karyotype than fetus) analysis can be performed immediately

  • villus culture = cells from central mesenchymal core (same karyotype as fetus) cultured for several days before analysis

• Errors (2%):

  • Mosaicism = cell line forming cytotrophoblast may develop abnormal karyotype while fetal cell line is normal

  • Maternal contamination = cells from maternal decidua may overgrow mesenchymal core cells

• Risks:

  • Spontaneous abortion (1%)

  • Perforation of amniotic sac

  • Infection

  • Teratogenesis: limb reduction defect

Cordocentesis

• = PERCUTANEOUS UMBILICAL BLOOD SAMPLING (PUBS)

  • DIAGNOSTIC CORDOCENTESIS

    • Hematocrit

    • Karyotype

    • Immunodeficiency: chronic granulomatous disease, severe combined immunodeficiency

    • Coagulopathy: von Willebrand syndrome, factor deficiency

    • Platelet disorder: alloimmune / idiopathic thrombocytopenic purpura

    • Hemoglobinopathy: sickle cell anemia, thalassemia

    • Infection: toxoplasmosis, rubella, varicella, cytomegalovirus, parvovirus

    • Hypoxia / acidosis

  • THERAPEUTIC CORDOCENTESIS

    • Intravascular fetal transfusion (fresh rh-negative CMV-negative leukodepleted irradiated packed cells compatible with mother infused at 10 15 mL/min)

    • Direct delivery of medication to fetus

Multiple gestations

Occurrence:

P.1021

• uterus large for dates

• may have elevated hCG, HPL (human placental lactogen), AFP levels

Perinatal morbidity & mortality compared with singletons:

Twin Pregnancy

Zygote = fertilized egg

Monozygotic Twins (1/3)

• = identical TWINS

• = division of a single fertilized ovum during earliest stages of embryogenesis (chorion differentiates 4 days and amnion 8 days after fertilization)

• Incidence: 1:250 birth (constant around the world)

• Predisposing factors:

  • Advanced maternal age

  • In vitro fertilization

    same sex + identical genotype

Dichorionic Diamniotic Twins (30%)

• = separation at two-cell stage (= blastomere) approximately 60 hours / <4 days after fertilization

• 2 separate fused / unfused placentas

• membrane >2 mm due to 2 separate chorionic sacs + 2 separate amniotic sacs (92% accurate for dichorionic diamniotic twins)

• twin peak sign = triangular projection of placental tissue insinuated between layers of intertwin membrane